1. Technical Field
The present invention relates to a handler which conveys a part, and more particularly to a handler provided with a temperature control unit for controlling the temperature of a part, and a part inspecting apparatus which includes the handler.
2. Related Art
A typical part inspecting apparatus which inspects the electric characteristics of an electronic part has a handler which conveys the electronic part before and after inspection between a tray on a base and an inspection socket. One such part inspecting apparatus inspects the electric characteristics of an electronic part kept in a low-temperature condition of 0° C. or lower.
For example, JP-A-2004-347329 discloses a method for cooling an electronic part to a low-temperature condition. According to the method of JP-A-2004-347329, a tray containing a plurality of electronic parts is placed on a stage. An inner passage is equipped inside the stage. Compressed air in a dry condition is cooled, and is supplied under the compressed and cooled condition to the inner passage of the stage. As a result, the tray is cooled via the stage, whereby the electronic parts can be cooled via the tray.
In addition to the technology shown in JP-A-2004-347329, there is another method for cooling an electronic part. According to this method, liquid nitrogen is supplied to the inner passage of the stage. This method can rapidly cool the stage, but produces the possibility of vaporization of a part of the liquid nitrogen within the inner passage of the stage. The volume of liquid nitrogen becomes approximately 700 times larger when vaporized at atmospheric pressure. Thus, the stage containing the inner passage and a discharge channel through which liquid nitrogen is discharged from the stage are required to have a sufficient level of pressure resistance for enduring the pressure fluctuations produced by vaporization of liquid nitrogen. Moreover, while the supply amount of liquid nitrogen is controlled such that the temperature of the stage changes to a target temperature, there is a possibility that the stage is excessively cooled to supply heat required for vaporization of liquid nitrogen within the inner passage of the stage.